脱乙酰壳多糖处理增加人参细胞皂苷的累积和皂苷合成关键酶基因的转录  

Chitosan Treatment Raises the Accumulation of Saponin and the Transcriptional Level of Genes Encoding the Key Enzymes of Saponin Synthesis in Cultured Panax ginseng Cells

作　　者：胡向阳[1] 张文清[2] 方建颖[1] 蔡伟明[1] 汤章城[1] 

机构地区：[1]中国科学院上海生命科学研究院植物生理生态研究所,上海200032 [2]华东理工大学化学与制药学院,上海200237

出　　处：《植物生理与分子生物学学报》2002年第6期485-490,共6页Journal Of Plant Physiology and Molecular Biology

基　　金：国家自然科学基金资助项目 (批准号 3 9870 0 5 0 )

摘　　要：脱乙酰壳多糖处理可以诱导人参细胞产生H2 O2 ,增加人参皂苷的累积 ,提高鲨烯合酶 (squalenesynthase,GSS)与鲨烯环氧酶 (squaleneepoxidase,GSE)基因的转录水平。质膜NADPH氧化酶的抑制剂DPI,H2 O2 的淬灭剂DMTU与DHC可以抑制脱乙酰壳多糖的这些效应 ,暗示脱乙酰壳多糖可以活化质膜NADPH氧化酶而产生H2 O2 ,H2 O2 进而作为第二信使诱导gss与gse基因转录以及皂苷的合成。质膜钙通道抑制剂LaCl3与内质网钙通道抑制剂RR ,以及蛋白激酶抑制剂K2 5 2a都能削弱脱乙酰壳多糖促进皂苷积累和gss、gse转录的效应 ,说明胞内Ca2 + 浓度的升高与蛋白质磷酸化都参与了脱乙酰壳多糖诱导的gss。Chitosan treatment can induce the product of hydrogen peroxide (H 2O 2) (Fig.1) and accumulation of saponin(Fig.4). Such chitosan induction is dose dependent(Figs. 1 and 4). It suggests the presence of a receptor for chitosan. Chitosan treatment can raise the transcriptional level of genes encoding squalene synthase (GSS) and squalene epoxidase (GSE) (Fig.6). DPI (an inhibitor of plasma membrane NADPH oxidase), DMTU or DHC (the scavengers of H 2O 2) suppress the increment of transcription of gss and gse (Fig.7), and the accumulation of saponin(Fig.5). The suppression indicates that chitosan activates NADPH oxidase of plasma membrane and induces the production of H 2O 2. H 2O 2 then acts as the secondary messenger to result in the induction of the transcription of gss and gse and the synthesis of saponin. The experiments of special inhibitors indicate that the increment of cytosolic Ca 2+ and protein phosphorylation are involved in the process of induction in cultured ginseng cells treated by chitosan (Figs. 3, 5 and 7).

关 键 词：脱乙酶壳多糖处理 人参细胞 皂苷 累积 合成酶 鲨烯 过氧化氢 基因转录 

分 类 号：S188[农业科学—农业基础科学]